基于浓度-吸光值函数预测土壤速效磷占比数据

土壤速效磷是指土壤中易被作物吸收利用的磷素，是表征土壤磷素供应状况的重要指标之一，及时测定和了解土壤中速效磷占比情况及其变化，对指导磷肥的施用是十分必要的。另外按照土壤样品号结合地理信息系统（GIS）技术，将各地点的土壤数据和信息进行深度整合和分析，绘制土壤速效磷占比地图，以直观的可视化形式呈现给用户。土壤速效磷浓度-吸光值函数是用于检测土壤中速效磷占比的方法，它是基于测定不同浓度的速效磷溶液在相同条件下吸收光谱从而测定磷离子的原理制成的。首先，包括4个标准点分别为2g/L、3g/L、5g/L和10 g/L，用原子吸收分光光度计测量出这4个标准点的吸光值‌，从而可以确定出浓度-吸光值函数（Y=10.56*X-0.84，其中X为速效磷溶液浓度，Y为吸光值)；其次，将土壤样品重量为AKg配制成10L的速效磷溶液，再用原子吸收分光光度计测量出该溶液的吸光值Y1，根据第一步得出的浓度-吸光值函数反推算出速效磷溶液浓度X1；最后，速效磷在土壤中的占比=速效磷的重量/土壤样品重量=10*X1/（A*1000）。

Available phosphorus in soil refers to the phosphorus fraction readily absorbable by crops, and is one of the important indicators characterizing soil phosphorus supply capacity. Timely measurement and understanding of the proportion and dynamic changes of available phosphorus in soil are essential for guiding phosphate fertilizer application. In addition, combined with Geographic Information System (GIS) technology based on soil sample numbers, soil data and information from various locations are comprehensively integrated and analyzed, and a map of soil available phosphorus proportion is drawn to present to users in an intuitive visual format. The concentration-absorbance value function of soil available phosphorus is a method for detecting the proportion of available phosphorus in soil, which is developed based on the principle of determining phosphorus ions by measuring the absorption spectra of available phosphorus solutions with different concentrations under identical conditions. First, four standard points with concentrations of 2 g/L, 3 g/L, 5 g/L and 10 g/L are prepared. The absorbance values of these four standard points are measured using an atomic absorption spectrophotometer, so that the concentration-absorbance value function can be established (Y=10.56*X - 0.84, where X is the concentration of the available phosphorus solution, and Y is the absorbance value). Second, a 10 L available phosphorus solution is prepared using a soil sample weighing A kg, then the absorbance value Y1 of this solution is measured using an atomic absorption spectrophotometer, and the concentration X1 of the available phosphorus solution is reversely calculated based on the concentration-absorbance value function obtained in the first step. Finally, the proportion of available phosphorus in soil = weight of available phosphorus / weight of soil sample = 10*X1/(A*1000).